The present invention is directed to a modular grass turf tile system, and more particularly, to a system for producing and placing large standardized turf sections to form and maintain a playing surface of an athletic field or any other vegetative surface.
There has been a movement in professional sports, such as football, to use natural turf surfaces, since there is a perception that natural turf surface has more give and lowers the risk of injury to players as well as the severity of injuries encountered in comparison to playing on artificial turf surfaces. This provides additional protection for the players as well as team owners who incur financial losses when players are injured. However, a drawback to natural turf playing surfaces has always been that the playing surface becomes worn through use, and it is not possible to grow or maintain a playing field in top condition over the course of an entire season.
Devices for cutting and picking up strips of sod which are then transferred to a truck or trailer for placement at a new location are known. These devices generally cut long strips of sod which are then rolled up and unrolled at a new location. However, this results in many bumps and joints in the final surface where the sod is placed due to inconsistent depths and multiple handling of the sod. Additionally, the strips may be too small to provide reliable self-anchoring capability during heavy use, and sufficient time must pass for the root system to grow into the existing soil base. While utilizing strips of sod may be acceptable for residential lawns, they may not suitable for athletic fields.
In order to address this problem one known device has been provided for picking up a large area of sod. The device utilizes a plurality of generally vertical teeth which are attached to a frame. A grass area which is to be picked up is undercut and the frame is then lowered onto the grass area such that the generally vertically oriented teeth penetrate the surface. After the teeth have pierced the sod, alternate rows of teeth are pivoted in opposite directions and assume an inclined orientation to secure the sod to the frame. This allows the sod to be harvested from the area where it was grown and placed in a final position. However, because the teeth penetrate the sod generally vertically and are then shifted to an inclined angle, this can cause damage to the sod, affecting its stability. Additionally, after the lifting device is withdrawn, the holes or openings in the sod have a high overhead observable which may be difficult to close in a relatively short time period utilizing conventional equipment, such as rollers. This makes the surface less desirable for use on an athletic field.
Another known device also allows movement of large turf section in order to replace a damaged portion of an athletic field. The device can be used to move a substantially large piece of turf and includes cutting knives mounted along the edges of a frame to sever the replacement turf from a section of ground, as well as a plurality of semicircular tines which are mounted on parallel shafts. The device is positioned over a desired area of turf to be harvested, and the knife blades are then used to cut the turf free. The shafts are then rotated such that the semicircular tines pierce the surface of the turf in order to secure the turf for subsequent lifting. The replacement section is then used as a permanent replacement for a section of damaged turf which is cut and removed from a playing surface. However, in this known device, the semicircular tines pierce the turf generally vertically, again leaving a greater overhead observable opening once the turf has been placed and the apparatus has been removed. Additionally, the configuration of the curved tine can result in the turf being damaged or buckling if the tine does not insert cleanly.
Another known device is used to place a turf product which is located on a pallet temporarily in position in a track surface or on a portion of an athletic field, such as the infield area of a baseball field which is being converted for use as a football field. The turf/pallet combinations are placed in recesses in the surface which are large enough to accommodate the turf and the pallet. However, this can result in a playing surface which may not have a stable feel, since the temporarily positioned turf areas are supported on hollow pallets. Another known system utilizes a similar arrangement of pallet supported turf units which are connected together to form the surface of a playing field. Placement and removal of the turf pallets are accomplished by using a forklift which engages the pallet or by cutting holes down through the turf to the pallet such that generally vertically oriented lifting rods can be connected to the pallet.
It would therefore be desirable to provide a grass turf tile system which allows for the easy placement and replacement of a natural turf surface on an athletic playing field in which the entire playing surface or a substantial portion of the playing surface is formed from replaceable natural grass turf sections that are stable in use, provide instant playability, and which can be easily and quickly maintained. This would provide the benefit of a natural turf playing surface which can be maintained in top condition throughout an entire season by easily replacing or rotating grass turf sections as they become worn.